Last night I dozed off on the sofa and was awakened by a cracking noise which I quickly traced to a plug on the wall which was clearly sparking inside the case. Alarmed, I unplugged it, turned it off and checked the trip switches but nothing else seemed untoward.
The plug in question runs to a four-socket extension. Plugged into the four sockets were a TV soundbar, two games consoles (and Xbox 360 and a PS4) and some incandescent Christmas tree lights, none of which were actively drawing power at the time this happened.
Today, presuming the extension to be at fault, I went out and got a new one with surge protection. I plugged the Christmas tree lights in first, and it seemed fine. Then I plugged in the PS4 and - without turning the console on - the surge protection tripped and the lights went out. Puzzled, I repeated this and got the same result.
I then plugged in the lights, Xbox and soundbar and everything seemed fine. Then I added the PS4 and there was no effect. I tried turning the Xbox on and the tree lights briefly went out, then returned. I turned that off and turned the PS4 on: no effect.
I cannot recall whether I'd ever seen this happen before: I have a vague memory of this extension sparking briefly once or twice when power was drawn. But this was prolonged sparking, enough to wake me from sleep. Also I have never had issues plugging in the PS4 before, but we don't normally run Christmas tree lights from this extension.
What's going on here? Should I be worried, or is the surge protection enough to keep me safe? Do I need to swap things around or unplug things when not in use?